Satellite broadcasting systems for transmitting programming content have become increasingly popular in many parts of the world. Direct Broadcasting Satellite (DBS) systems transmit television programming content, for example, to a geo-stationary satellite, which broadcasts the content back to the customers. In such a wireless broadcast environment, the transmitted programming can be received by anyone with an appropriate receiver, such as an antenna or a satellite dish.
In addition, a number of satellite broadcasting systems have been proposed or suggested for broadcasting audio programming content from geo-stationary satellites to customers in a large coverage area, such as the continental United States. Proposed systems for providing digital audio broadcasting (DAB), for example, are expected to provide near CD-quality audio, data services and more robust coverage than existing analog FM transmissions. Satellite broadcasting systems for television and radio content provide potentially national coverage areas, and thus improve over conventional terrestrial television stations and AM/FM radio stations that provide only regional coverage.
Satellite broadcasting systems transmits digital music and other audio information from an uplink station to one or more mobile receivers. Satellite broadcasting systems typically include a plurality of satellites and terrestrial repeaters operating in a broadcast mode. The satellites are typically geo-stationary, and are located over a desired geographical coverage area. The terrestrial repeaters typically operate in dense urban areas, where the direct line of sight (LOS) between the satellites and the mobile receiver can be blocked due to the angle of elevation and shadowing by tall buildings.
Many digital audio broadcasting systems utilize a transmitter identifier information signal to permit test equipment to associate the received signal with any terrestrial repeater(s) that generate the TII signal. The European digital audio broadcasting standard, for example, set forth in “Radio Broadcasting Systems: Digital Audio Broadcasting to Mobile, Portable and Fixed Receivers,” European Telecommunications Standard: ETS 300 401 (May 1997), provides synchronization, null and data symbols as part of the OFDM signal. Under the European digital audio broadcasting standard, the TII signal is transmitted in the active bandwidth using dedicated synchronization symbols that are multiplexed in time with the user data. A need exists for a method and apparatus for transmitting a TII signal with reduced overhead and increased capacity. A further need therefore exists for a method and apparatus for transmitting a TII signal that optionally makes the TII information available in all symbols.